Immunity (ARM) and Immunity (BTS) state: Any Ammunition that requires a Saving Roll using the ARM/BTS Attribute is treated as Normal (N) Ammunition. Its special effects, and any MODs to the Attribute and number of the Saving Rolls are ignored. If the Weapon, Skill, or piece of Equipment used in the Attack has Traits, the Trooper is completely immune to any of those Traits that cause States, refer to inflicting Wounds, or reduce the Attributes of the target. For example, State: Dead, Continuous Damage, or ARM=0. Do Immunity skills, such as Immunity (ARM) allow troopers to ignore the modifiers to the saving roll imposed by Mods such as PS=X or SR-Y? For example, does this mean that a CC attack made with a CCW hitting a trooper with a relevant immunity always hits at PS8? Similarly, are armour saves made against a TAG's HMG made against an Immunity (ARM) trooper made at PS5? This seems like a major oversight in the transition to damage resolution, and I think clarification and errata is necessary.
Troopers with immunity dont ignore those skills effects, as you noted, only ammunition effects are ignored.
The second sentence is referencing the first sentence. "It's special effects" refers to Ammunition that requires a Saving Roll using the ARM/BTS Attribute and any MODs to the Attribute is referring to the affected Attribute in the brackets of the skill in question (e.g. Immunity (ARM) or Immunity (BTS)). PS is not a part of either of these clauses, so MODs to PS aren't affected by Immunity.
Mods to PS are definitely not affected, but what about mods to SR? PS is from the point of view of the trooper causing the damage, while the SR is from the point of view of the trooper receiving the damage (the one that may have Immunity (ARM)). Saving Roll: To calculate the Success Value of the Saving Roll, the player must take the target's ARM or BTS Attribute value, as appropriate, and add the following to it: The Weapon's PS value. The (+3) MOD due to Partial Cover, if applicable. Apply other MODs (+ or -) due to Special Skills or rules, if any. Immunity (ARM): Any Ammunition that requires a Saving Roll using the ARM Attribute is treated as Normal (N) Ammunition. Its special effects, and any MODs to the Attribute and number of the Saving Rolls are ignored. If the Weapon, Skill, or piece of Equipment used in the Attack has Traits, the Trooper is completely immune to any of those Traits that cause States, refer to inflicting Wounds, or reduce the Attributes of the target. For example, State: Dead, Continuous Damage, or ARM=0. (Emphasis on red text is mine) So does this mean Immunity (ARM) does not prevent modifiers that are not explicitly included in the ammunition of a weapon? Such as Chief Jeong's Combi Rifle (AP)? This is clearly different from a weapon such as an AP Marksman Rifle which lists AP in it's AMMO and SR:ATTRIB areas of the weapon, while Chief Jeong's Combi Rifle does not. Obviously there's some room for common sense here, but with regards to consistency, I can't actually seem to find a reason why SR-X wouldn't be ignored by Immunity (ARM) other than because people think so. Would this not also explain why some weapon modifiers in the game use PS=X, while others use SR-Y? PS=X modifies the weapon and would not be ignored by Immunity (ARM) SR-Y modifies the save and could be ignored by Immunity (ARM) EDIT: Since writing this, I have been convinced. I still think it would be neat and would have explained the difference between PS=X and SR-Y, but it's clearly not the intention.
Combi Rifle (AP) gives AP ammunition to combi rifle (reference: Modifiers example, BS Attack (Shock) means that the user adds Shock Ammunition to all their BS Attacks.), so it’s ignored by Immunity(ARM). It’s actually clear. Immunity(Arm) ignores ~any MODs to the Attribute~, and “the Attribute” here is armor. SR-X gives a mod to Saving Roll, not armor, so it’s not ignored by Immunity(Arm). HRL might be an example for this case. HRL has two modes: template mode with PS 6 and hit mode with PS 5. PS=X changes PS of all modes of HRL to X (for example, Blink HRL with PS=5 always has PS 5 for both hit and template mode). SR-1 makes PS of template mode to 5 and hit mode to 4. That’s the difference. And both cases don’t change values of Armour attribute, so they are not affected by Immunity(Arm).
